China restated its warning to Japan and some countries outside the South China Sea of interfering in the disputed waters and destabilizing the region, after the Japanese government approved a defense white paper on Tuesday.

On the South China Sea issue, Japan tried its best to complicate the situation by driving a wedge between China and countries involved in the dispute for its own gain, Wu Qian, a spokesperson for the Ministry of National Defense, said on Tuesday.

"We would like to inform Japan that freedom of navigation in the South China Sea has not been disrupted. Japan and other outsiders are interfering in the issue and harming regional peace and stability," Wu said.

Experts said they believe the white paper highlights Japan's continuing justification of its own militarization and attempt to draw support for the constitutional amendment.

Japan devoted 30 pages of the 480-page document on China's national defense and normal and legal maritime activities in the East and South China seas, the Xinhua News Agency reported on Tuesday.

The document said China's reclamation on the islands and reefs in the South China Sea is threatening regional security, and Japan is seriously concerned about it, China News Service reported.

Japan's cabinet is trying to prove that China is unilaterally changing the situation and threatening regional and Japanese security, Lü Yaodong, director of the Institute of Japanese Studies at the Chinese Academy of Social Sciences, told the Global Times.

Since Japanese Prime Minister Shinzo Abe is preparing to have Article 9 of the country's constitution amended, which states that the Japanese people forever renounce war as a sovereign right of the nation, hyping the "China threat" can provide excuses for the constitutional amendment, otherwise Japan's militarization is unconstitutional, Lü said.

Dismissing the "China threat" as groundless, Lü stressed that China's military development is reasonable, and that China is making great efforts to resort to peaceful means to settle disputes.  

The white paper comes after an arbitral tribunal, with judges mostly picked by Shunji Yanai, a Japanese right-winger, issued a "biased and illegal ruling" on the South China Sea dispute on July 12. China has dismissed the ruling as "null and void with no binding force."

In the white paper, the Japanese government urged China to respect the ruling and support the Philippines'"illegal" sovereignty claims, Xinhua reported. Japan is placing greater importance on the waters than before because it has to face China alone in terms of disputes over the East China Sea, of which the US is reluctant to get involved. While in the South China Sea, Japan can have partners such as the Philippines, Song Zhongping, a Beijing-based military expert, told the Global Times.